This is a complete rewrite to better support all the features that I was trying to get into v2. There are a few breaking changes from v2 beta, which some (myself included) was using in production, so I'm skipping a stable v2 release and going straight to v3.

Here are some of the new things available, but check the updated docs.

Dynamic query builder based on raw sql
Realtime subscribe to db changes through logical replication
Multi-host support for High Availability setups
Postgres input parameter types from ParameterDescription
Deno support
Cursors as async iterators
.describe() to only get query input types and column definitions
Support for Large Objects
max_lifetime for connections
Cancellation of requests
Converted to ESM (with CJS support)
Typescript support (Credit @minigugus)

Breaking changes from v2 -> v3

Cursors are always called with Result arrays (previously cursor 1 would return a row object, where > 1 would return an array of rows)
.writable() and .readable() is now async (returns a Promise that resolves to the stream)
Queries now returns a lazy promise instead of being executed immediately. This means the query won't be sent until awaited (.then, .catch, .finally is called) or until .execute() is manually called.
.stream() is renamed to .forEach
Returned results are now it's own Result class extending Array instead of an Array with extra properties (actually shouldn't be breaking unless you're doing something funny)
Parameters are now cast using the types returned from Postgres ParameterDescription with a fallback to the previously inferred types
Only tested with node v12 and up
Implicit array value to multiple parameter expansion removed (use sql([...]) instead)

Breaking changes from v1 -> v2 (v2 never moved on from beta)

All identifiers from sql() in queries are now always quoted
Undefined parameters are no longer allowed
Rename timeout option to idle_timeout
Default to 10 connections instead of number of CPUs
Numbers that cannot be safely cast to JS Number are returned as string. This happens for eg, select count(*) because count() returns a 64 bit integer (int8), so if you know your count() won't be too big for a js number just cast in your query to int4 like select count(*)::int